Prognostic Significance of Fatty Liver Index for the Development of Hypertension and Cardiovascular Events in Populations With Suboptimal Blood Pressure

Background: Suboptimal blood pressure (BP) is a precursor to clinical hypertension and is associated with BP-related morbidity and mortality. Non-alcoholic fatty liver disease, a metabolic disorder with an increasing incidence rate, is associated with cardiovascular diseases (CVDs). We investigated the association of fatty liver index (FLI) with incident hypertension and CVD outcomes in a large cohort of adults with suboptimal BP. Methods: We included 179,028 Koreans with suboptimal BP and no traditional risk factors from the National Health Insurance Service-National Sample Cohort, who underwent health examinations between 2009 and 2014. All subjects were divided into two groups based on their BP: ‘normal BP’ group (systolic BP [SBP] 120–129, diastolic BP [DBP] 80–84 mmHg), and ‘high-normal BP’ group (SBP 130–139, DBP 85–89 mmHg). The incidences of new-onset hypertension and major adverse cardiac and cerebrovascular events (MACCEs) were analyzed in the two groups across quartiles. Multivariate Cox proportional hazards regression analysis assessed the association between the FLI and primary outcome. Results: During a median follow-up of 8.3 years, 34,667 participants (19.36%) developed new-onset hypertension, which was significantly greater in the ‘high-normal BP’ group than in the ‘normal BP’ group (25.95% vs. 14.25%, P < 0.001). The incidence of new-onset hypertension was significantly higher in participants with higher FLIs according to the FLI quartile values in both groups. Additionally, 3,339 (1.87%) MACCEs were observed during the follow-up period. MACCEs occurred more frequently in the ‘high-normal BP’ group than in the ‘normal BP group’ (2.33% vs. 1.51%, P < 0.001). MACCEs were also associated with FLI quartiles. In the multivariable models adjusted for potential confounders, the hazard ratio for MACCEs comparing the highest vs. lowest quartiles of the FLI was 1.640 (95% confidence interval [CI], 1.409–1.910) and 1.363 (95% CI, 1.141–1.627) in the ‘high-normal BP’ group and ‘normal BP’ group, respectively. Conclusion: Over 8–9 years, 19.3% of Korean adults with suboptimal BP developed hypertension, and 1.87% experienced MACCEs without traditional risk factors. A higher FLI was independently associated with the development of hypertension and MACCEs. The FLI may be an important predictor of new-onset hypertension and adverse cardiovascular outcomes.